I found two interesting applications:
1. apply to base of tubes. Significant increase in impulse fidelity and clarity
2. apply to USB connector between streamer and DAC. Reduces vibration-borne interference of DA conversion, particularly resulting in less grain in the treble and better consistency of sound stage.
The application to speakers works on bass units to dampen unwanted resonance. On treble it is substantially riskier because the tweeter is more prone to seize up.
These are very desirable improvements, the lacquer is a true audiophile tweak.